The present invention relates to a process for manufacturing by extrusion helical members of plastic material, for example, in the shape of helical springs.
Such helical members can be used, for example, to surround tubing or piping which must be protected from shocks but these members can also be used in all sorts of applications.
The processes presently used to manufacture such helical elements or members consist of extruding a continuous filament of plastic material which is basically circular in section, then winding this filament helically on a fixed or rotating core or mandrel. The wound filament tends to harden as it cools so that a solid helical member finally results.
These known processes still have a certain number of disadvantages. They actually require careful implementation and precise adjustments. Moreover, they do not permit high production rates. More significant difficulties arise when an attempt is made to manufacture helical members with complex sections.